Adjustable relief valve for pressure cookers



1951 E. G. GRUNDSTROM 2,570,228

ADJUSTABLE RELIEF VALVE FOR PRESSURE COOKERS Filed Feb. 5, 1948 [91% 6. Gru/zo sfrom ww w Patented Oct. 9, 1951 ADJUSTABLE RELIEF VALVE FOR PRESSURE COOKERS Erik G. Grundstrom, Chicago, 111., assignor to Advance Aluminum Castings Corp., Chicago, 111., a corporation of Illinois Application February 5, 1948, Serial No. 6,393

7 Claims. 1

This invention relates to a new and improved relief valve for domestic pressure cookers and similar pressure receptacles.

The principal object of my invention is to provide, in a unitary assembly, a relief valve comprising a plurality of weights which may be used selectively in any one of a number of different combinations to weight the valve element accordingly and thus maintain whatever pressure is desired within the cooker.

The weights, in accordance with my invention, are all assembled in the tubular body of the valve and the lowermost one weights the valve element directly, the others above being provided with operating handles by means of which they, or as many of them as desired are arranged to be supported in the valve body, in raised retracted relationship to the lowermost weight, whereby the valve can be set quickly and easily to open at, say, five pounds steam pressure, when only the lowermost weight is in operative position, and open at, say, ten pounds pressure, when the second weight is added, and open at, say fifteen pounds pressure, when the third weight is added.

The invention is illustrated in the accompanying drawing, in which- Fig. 1 is a side view of a pressure cooker equipped with a relief valve made in accordance with my invention;

Fig. 2 is a side view of the relief valve removed from the cooker and shown on a larger scale, and

Fig. 3 is a cross-section on the line 33 of Fig. 2.

The same reference numerals are applied to corresponding parts in these three views.

Referring to the drawing, the reference numeral 4 designates the receptacle or body of the pressure cooker, and 5 the removable cover therefor. The cover 5 is arranged to be clamped resiliently in closed position in the open top of the receptacle by means of a handle 6 and spring 'i, the latter being turned by the handle to compress the gasket that is provided between the parts for a steam-tight seal. The housewife after placing the foodstuff to be cooked in the receptacle 4, sets the relief valve 8, either by experience or according to instructions, and then places the cooker over the gas burner or other source of heat. As the temperature rises within the cooker steam will, of course, be generated in the receptacle until the pressure is sufficient to open the valve 8. The steam escaping sounds a whistle 9 givin a warning to the housewife. Then, ac-

cording to what I consider the preferred practice, the housewife will re-setthe valve 8 for the high est possible pressure and remove the cooker from the source of heat. The valve 8 of my invention, as will soon appear, enables quicker and easier setting and resetting than previous designs of adjustable valves provided on pressure cookers. When the valve 8 is set for the highest pressure, as just mentioned, the pressure within the cooker will be maintained for a long time. After the cooker has been removed from the heat source and the food is subject to the existing temperature and pressure within the cooker for a certain length of time, which can be readily determined by simple experimentation with different foods being cooked, the housewife will open the valve 8 so that the steam pressure in the cooker is relieved and the cover 5 can be removed for access to the food. The present design, as will also appear soon, also enables easy opening of the valve, when that is necessary. The housewife, going by experience or instructions, knows that when she sets the valve 8 for a certain pressure the valve should open in a. certain number of minutes. assumin the heat source is operating properly and has been set properly. If the thermometer Iii indicates that the temperature (and consequently the pressure) within the closed cooker is rising too slowly Or too rapidly, the operator will adjust the source of heat accordingly to obtain the desired pressure (and temperature) at the end of the proper length of time. with certain foods to hold a pressure within the cooker for a predetermined length of time after said pressure has been obtained. The housewife may reset the valve 8, and, observing the thermometer Ill, she may adjust the source of heat to maintain said pressure.

The relief valve 8, in accordance with my invention, comprises a tubular body I I having a reduced threaded end portion [2 for threading with a steam-tight fit in an opening provided therefor in the cover 5. The smooth circular bore [3 of the body ll communicates at its lower end with the small co-aXial orifice 14 provided in the end portion l2, a tapered valve seat I5 being provided at the inner end of the orifice for cooperation with the tapered end of the longitudinally reciprocable relief valve [6. This relief valve is herein directly weighted by the cylindrical weight H, to which it is suitably rigidly attached, the weight I! being, of course, slidable freely in the bore 13. Additional weights, in whatever number desired, are also assembled in the bore l3 and adapted to be used selectively, one or more at a time, to supplement the weight I! to obtain whatever aggregate Furthermore it is frequently desirable 3 weight is desired, within the limits of the unit, and accordingly predetermine higher pressures at which the relief valve IE will open. In the present case two such additional cylindrical weights I8 and I9 are provided, both, of course, freely slidable in the bore 13, above the weight l7; There are diametrically opposed longitudinal slots 26 in the body l.l, and through these slots the weights I'!l 9 have their operating handles lla l9a projecting for convenient manipulation of the weights in setting the valve [,8 .or opening the same. There are diametricallyppposed notches or bayonet slots 2| and 22 opening from the slots 20 at two elevations above the'levelnfrthe"weights I! in which the handles I.8'a:and;I9 a:of weights l8 and I9 can be quickly releasably engagedifor support of these weights in raised retracted. positions relative to the weight [1. The notches are .spaced far enough apart so that the uppermost weight [9 will not interfere with the manipulation 'of'the weight ldif onlythat weight is torbelowered to=rest on the weight H. The downwardinclination of slots-2i andtEZ necessitates a slight amount of liftingof the-weights in withdrawing the handles from --the :slots. This is to .avoid danger-of the'weights dropping down accidentally. It will. also be seenithat tnesiots 2 ii extend do W n -.farenough--below the handles I la: to insure .pro-

per seating of :valve 1-6.

Inoperation, assumingthat the mass of weight .II-issuchthat Valve It will openat fivepounds pressure, then thehousewife can set the valve-t3 accordingly,-witl1only this lowermost weight in operativepositionif she desires to havet-hewarning whistles sounded when thatlpressureisob- *tained-the whistle iihhavingitsfbore .23 in open communication withthe lower end of bore .20. so -as-to :be sounded by the escapingsteam when valve L6 opens. -When the pressure cookeris used -for canning it is operated sometimes at five pounds pressure :and other-times at ten :pounds .pressure,- depending Onthe-Kindof .food being .prepared. Hence, assuming .that ,the mass .,of weight l-Eiadded to weight H is enough .to keep .the valve. It closed up toa pressure of ten pounds, L .the housewifegplaces weight E8. in .opera'tiveeposi- -tion ontop of weight lTfor operation at .that pressure. Forsome otherZ-foods requiringhigher .;-pressures to be cooked thoroughly, .the .third weight l9- may be placed ontop of weights l'l'. arid l8 to keep the valve. [6. closed up ;to,. a, pressure of say-.15 pounds, assuming themass of the three weights is equivalent to such an internal pressure in the cooker. Obviously as many additional weights maybeprovidedas needed foras Wide.

arange of pressuresras.aflgiven cookerimay,be

designed. When the pressurein thecooker islvto be relieved, as previously. mentioned -the weight or weights can be raised by means .o'fflthevhandle ther reduce likelihood. of Lthewoperator. vburning her fingers. The upper end of-Lthe body I l I is .closedby. a cap. '25. pinned, .as at"26, .orotherwise suitably secured in place.

-It is believed the foregoingjdescniption.conveys --.being so locatedas. to elevationin relation to said first weight for support-of the other weight in raised. retracted position whenthe. handles .on said other weight areengaged. in .said. bayonet 65.

.a goddunderstanding .oi'j the obj'ettsand,.aldvanciproc'ablein said body and supported by said valve member predetermining a pressure in the orifice necessary to unseat the valve member, an

operating zhandle projecting from said weight 'zthroughsaid slotto permit manuall lifting said -weighttolunseatsaid valve member from outside said body independently of the pressure in said orifice, at least one other Weight reciprocable in saidzbody and adapted to rest on the first weight to predetermine by the aggregate weight of the weights a higher pressure in the orifice :necessarytounseat -the valve member, .said 'bodyihaving a bayonet slot providedtherein communicatwith the longitudinal slot,-.and=an operating handle on-the second weight projecting therefrom 'for engagement selectively in either. of said slotsthe bayonet slot beingsso located 3.51130 818- vation in relation-to Said' first weight forgsupport of the other-v weight in raised retracted position when the handle onsaid other weightiis engaged; in said bayonet'slot.

we as senior-thin claim-l, ;.wherein the .opera nez nd s a a fih IS 'W i h L 1Q non-conducting l material.

3. ;A2 valve comprising a tubular body. having --.a

restricted orifices in one end and a valve;seat at the-inner-end ofsaidvori-ficea reciprocable waive member .,in.-.said ..;body r-arranged to engage v e atib vit sei d ar n rtw longitudinal -.slots provided -;l herein on diametrica ll opposi-tesides,;a Weight reciprocablein said body andr supported by said valve member predetern ning a;-pressure.;in'the orificenecessary to zunseatrthe ;valve;member, a. pair of operating handles projecting from said Weight onfidiametricallyropposite ,sides and operable .in' said slots to permit manually liftingrsaid,weight to-unseat V saidivalve member from outside said body: independently of the pressure-in -said orif ce at least one other weight reciprocable,in.,said:bodyqand adapted to.;rest on the ":first weight-to; predetermine: by. the aggregate :Weight of the weights ea highenpressure the -.or ifi ce necessary ;to u ns eat th r-vav e be f idmdrhfr ms b et's p v dedwth eineond ametrica y-opposite-sid communicating-with; the I longitudinal 's lots, ,and ZZ'IJEdPOf operating handleson the-second weight projecting therefrom Jon diametricallympposite sides forengagement.selectively in-either-the longitudinal slots or bayonet slots, the bayonetslots slots.

.4...A valveasset forth in=c1aim l,.wherein..the operating handles on the weights .-are .of ,.-nonconducting material.

. .5...A- valvecomprising va tubular body havinga restricted orifice. in oneend and avalveseatat .the. inner end of said orifice, a reciprocablesvalve member .in...said .body arranged to engagethe valveseat by;.gravity,.said, body. having -a dongltudinal slot provided .therein, a weight reciprocable, in sa d bodyandrsupp rt -v. by. said valve member predetermining a pressure in the orifice necessary to unseat the valve member, at least one other weight reciprocable in said body and adapted to rest on the first weight to predetermine by the aggregate weight of the weights a higher pressure in the orifice necessary to unseat the valve member, said body having a bayonet slot provided therein communicating with the longitudinal slot, and an operating handle on the second weight projecting therefrom for engagement selectively in either of said slots, the bayonet slot being so located as to elevation in relation to said first weight for support of the,

other weight in raised retracted position when the handle on said other weight is engaged in said bayonet slot.

6. A valve as set forth in claim 5, wherein the operating handle on said last mentioned weight is of non-conducting material.

'7. A valve comprising a tubular body having a restricted orifice in one end and a valve seat at the inner end of said orifice, a reciprocable valve member in said body arranged to engage the valve seat by gravity, said body having two 1ongitudinal slots provided therein on diametrically opposite sides, a weight reciprocable in said body and supported by said valve member predetermining a pressure in the orifice necessary to unseat the valve member, at least one other weight reciprocable in said body and adapted to rest on the first weight to predetermine by the aggregate weight of the weights a higher pressure in the orifice necessary to unseat the valve member, said body having bayonet slots provided therein on diametricall opposite sides communicating with the longitudinal slots, and a pair of operating handles on the second weight projecting therefrom on diametrically opposite sides for engagement selectively in either the longitudinal slots or bayonet slots, the bayonet slots being so located as to elevation in relation to said first weight for support of the other weight in raised retracted position when the handles on said other weight are engaged in said bayonet slots.

ERIK G. GRUNDSTROM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 80,461 Davis July 28, 1868 686,976 Kelly Nov. 19, 1901 1,474,192 Gessler Nov. 13, 1928 2,200,903 Stephens May 14, 1940 2,294,746 Grundstrom Sept. 1, 1942 

